<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>轮廓outline(了解)</title>
    <style>
    div{
        width: 100px;
        height: 100px;
        background: #ff2d51;
        outline:10px solid #44cef6; 
     }
     input{
         margin-top: 50px;
         outline: none;
     }
    </style>
</head>
<body>
    <!--
        了解
    -->
    <div>

    </div>
    <input type="text">
</body>
</html>